Chem Exam 2 Intext questions (ch 4-6)
How many grams of oxygen would form with 2.13 g of Mercury (II) oxide? Use the following equation: 2HgO (s)⇒ 2Hg (l) + O2(g)
0.0787 g O2
What is the angle between electron groups if they have tetrahedral geometry?
109.5
Using the equation for the Haber-Bosch process here : 4NH3 +3O2⇒2N2+ 6H2O How many liters of nitrogen gas would be produced if we start with 22.3 L of ammonia? Write your answer as a number with correct sig figs only. Be sure to use the conversion factor of 22.4 L= 1 mole of any gas and you can use the shortcut if you would like.
11.2
Using the equation for winemaking, let's go in the opposite direction and go from volume to mass. How many grams of glucose are needed to produce with 28.3 L of carbon dioxide? Enter your answer as a number with correct sig figs only.
114
Acetylene gas (C2H2) is produced as a result of the following reaction. CaC2(s) + 2H2O(l) --> C2H2(g) + Ca(OH)2(aq) If 3.20 moles of CaC2 are consumed in this reaction, how many grams of H2O are needed?
115 g H2O
C3H8 + 3O2 → 3CO2 + 4H2 How many moles of oxygen are necessary to react completely with 4.0 moles of propane C3H8?
12 moles O2
Copper II chloride reacts with Sodium nitrate. CuCl2 +2NaNO3 ---> Cu(NO3)2 + 2NaCl If 15 g of Copper II chloride react with 20 g of Sodium nitrate, how much sodium chloride can be formed-use four sig figs in your response? Hint: Smallest amount is that 'theoretical yield.' Bear in mind, this answer will be used in the continuation of this problem to achieve the objective of finding amount of excess reactant left over.
12.36 g NaCl 15CuCl2/ 134.45 g CuCl2 x 1 mol CuCl2/ 1 mol CuCl2 x 2 mol NaCl/ 1 mol NaCl x 55.4 g NaCl= 12.36 g NaCl=answer since we do not have enough CuCl2 to make any more. 20. g NaNO3/ 84.995 g NaNO3 x 1 mol NaNO3/ 2 mol NaNO3 x 2 mol NaCl/ 1 mol NaCl x 55.4 g NaCl= 13.04 g NaCl
Mg(s) + 2HCl(aq) -> MgCl2(aq) + H2(g) How many grams of HCl are consumed by the reaction of 2.50 moles of magnesium?
183g HCl
How many electrons can exist in an orbital?
2
When placing aluminum into sulfuric acid, aluminum sulfate and hydrogen gas is formed. 18.2 g of aluminum produces _____ g of hydrogen gas.
2.05
Write a balanced chemical equation for the following description:Aluminum metal reacts with copper (II) chloride to produce aluminum chloride and copper metal.
2Al + 3CuCl2 ---> 2AlCl3 + 3Cu
Write the molecular equation that show the reaction of Iron III chloride with magnesium metal.
2FeCl3 (aq) + 3Mg (s) -> 3MgCl2 (aq) + 2Fe (s)
Write a molecular equation (predict products) for the gas evolution reaction that occurs when you mix aqueous nitric acid and aqueous sodium carbonate.
2HNO3 (aq) + Na2CO3 (aq) ⇒ H2O (l) + CO2 (g) + 2NaNO3 (aq)
For the following reaction, determine what the products of this reaction will be. When you have predicted the products, balance the equation and use a table of solubility products to determine which of the products (if any) will precipitate. Assume all reactions take place in water. ____ NaC2H3O2 + ____ H2SO4 --->
2NaC2H3O2 (aq) + 1H2SO4 (aq)---> Na2SO4 (aq) + 2CH3COOH (aq) (no precipitate)
Hydrochloric acid can dissolve solid iron according to the following reaction: Fe(s) + 2HCl(aq)⇒FeCl2(aq) +H2(g) How much HCl could dissolve a 2.8 g iron padlock? Express your answer as a number with correct sig figs only.
3.7
The Lewis structure of oxygen has ------ valence electrons. Express your answer as a number
6
Using the equation above : 4NH3 +3O2⇒2N2+ 6H2O How many liters of nitrogen gas would be produced if we start with 13.28 L of ammonia? Write your answer as a number with correct sig figs only. Be sure to use the conversion factor of 22.4 L= 1 mole of any gas and you can use the shortcut if you would like.
6.64
Sodium chloride forms in this reaction between sodium and chlorine. How many moles of NaCl result from the complete reaction of 3.4 moles of Cl2? Assume that there is more than enough Na. Express your answer as a number with two sig figs only.
6.8
How many moles of NaCl result from the complete reaction of 3.4 mol Cl2? Assume more than enough Na. 2Na(s) +Cl2(g) ⇒2NaCl(s)
6.8 mol NaCl
K3PO4 + Al(NO3)3→ 3KNO3 + AlPO4 How many moles of potassium nitrate are produced when 2.5 moles of potassium phosphate react? Write your answer as number only.
7.5
Using the equation for winemaking, how many liters of carbon dioxide would be produced with 287.62 g of glucose? Enter your answer as a number with correct sig figs only. C6H12O6 ---> 2C2H5OH + 2CO2
71.5
How many valence electrons are in the noble gases (Group VIIIA) all the way to the right of the periodic table.
8
Consider the following equation which shows the combustion of butane used in lighters: 2C4H10(g) + 13 O2(g) ⇒8CO2(g) +10 H2O (l). How many grams of water can be produced from 5.22 g of butane (C4H10)?
8.09 g H2O
10.4 g of Arsenic reacts with 11.8 g of sulfur to produce 14.2 g of As2S3. What is the percent yield? Write your answer as a number with two sig figs only.
83
2KClO3 → 2KCl + 3O2 How many moles of oxygen are produced by the decomposition of 6.0 moles of potassium chlorate?
9.0 moles O2
Solid aluminum reacts with gaseous chlorine. If you begin with 0.552 mol of aluminum and 0.887 mol of chlorine, what is the limiting reactant and theoretical yield of the product in moles?
Al, 0.552 mol AlCl3
10.4 g of Arsenic reacts with 11.8 g of sulfur to produce 14.2 g of As2S3. What is the limiting reactant?
As
What is the octet rule?
Atoms bond together by either transferring or sharing electrons so that all atoms obtain an outer shell with 8 electrons.
Lewis theory predicts that the formula for a compound between barium and sulfur:
BaS
Which element has the highest electron affinity?
C
Which of the following answers shows a complete and balanced equation showing the combustion of propane (C3H8)?
C3H8 (g) + 5O2 (g) -> 3CO2 (g) + 4H2O (l)
Lewis theory predicts that the formula for a compound between flourine and calcium is:
CaF2
What should not be done when predicting products of reactions?
Carrying over subscripts.
Please show the net ionic equation for the reaction of Copper II chloride with silver acetate.
Cl- (aq) + Ag+ (aq) -> AgCl (s)
Using the reaction of 2 Na (s) + Cl2 (g) ---> 2 NaCl (s) If we have 53,2 g Na and 65.8 g of , what is the limiting reactant? Answer by writing the word for the product (not the formula).
Cl2
Please show the ionic equation of the reaction of Copper II chloride with silver acetate.
Cu2+ (aq) + 2Cl- (aq) + 2Ag+ (aq) + 2C2H3O2- (aq) -> Cu2+ (aq) + 2C2H3O2- (aq) + 2AgCl (s)
The molecular equation that shows the reaction of Copper II chloride with silver acetate is ------- Please show states of matter in parentheses and depict ---> to show the reaction.
CuCl2(aq) + 2AgC2H3O2(aq) ---> Cu(C2H3O2)2(aq) + 2AgCl(s)
What is fermentation? Remember this relates to our mass to volume stoichiometry problems.
Fermentation is the breakdown of carbohydrates in an environment where there isn't oxygen.
Which of the following answers shows a complete and balanced equation showing the reaction of nitric acid with potassium hydroxide?
HNO3 (aq) + KOH (aq) --> KNO3 (aq) + H2O (l)
Why is hydrogen considered an exception to the octet rule?
It only needs 2 valence electrons.
Lewis theory predicts that the formula for a compound between potassium and sulfur is:
K2S
Which of the following elements have the least metallic character?
Li
How is metallic character defined?
Metallic character is defined as how readily an atom can lose an electron.
Write an equation for the precipitation reaction (if any) that occurs when solutions of lead (II) acetate and sodium sulfate are mixed. If no reaction occurs, choose NO REACTION.
Pb(C2H3O2)2 (aq) + Na2SO4(aq)⇒ PbSO4 (s) + 2NaC2H3O2(aq)
What is the net ionic equation for the following reaction? Pb(NO3)2 (aq) + 2LiCl (aq) ⇒ PbCl2 (s) + 2LiNO3 (aq)
Pb2+ (aq) + 2Cl- (aq) ⇒PbCl2 (s)
Identify the reactant(s) in the following reaction: 2KClO3 ---> 2KCl + 3O2
Potassium chlorate KClO3 both a and b
Which of the following elements have the lowest ionization energy?
Rb
Write a balanced equation for the reaction between solid silicon dioxide and solid carbon to produce solid silicon monocarbide and carbon monoxide gas.
SiO2(s) + 3C(s) ---> SiC(s) + 2CO(g)
What is step 5(the most important step) in stoichiometry?
Use mole ratio from balanced chemical equation.
What is step 5 in stoichiometry problems?
Use your mole ratio from the balanced chemical equation. (The mole conversion factor comes from the coefficients of the balanced chemical equation.)
Why don't the noble gases bond very often?
a These do bond but are typically exceptions to normal rules. b They have 2 valence electrons so have a filled shell. c They have 8 total valence electrons so have a filled shell. d A and C.
The following reaction: HCl(aq) + KOH (aq)---> KCl(aq) + H2O(l) is an reaction
acid-base
What is the formula for percent yield?
actual yield/theoretical yield x 100%
A molecule that is polar (has uneven charges/is asymmetrical and not sharing electrons evenly) is also known as a:
dipole
Which of the following show evidence of a chemical reaction?
formation of gas
What is the molecular geometry of carbon dioxide?
linear
What does l refer to when placing phases within a chemical equation?
liquid
In this type of reaction, two aqueous compounds produce a solid product.
precipitation
The following reaction: AgNO3 (aq) + KCl (aq) → AgCl (s) + KNO3(aq) is a: reaction
precipitation
What type of reaction is the following: 2KI(aq) + Pb(NO3)2 (aq)---> PbI2(s) +2KNO3(aq)
precipitation
Classify the reaction: 3Pb (s) + 2H3PO4 (aq) ---> 3H2 (g) + Pb3(PO4)2 (s)
single replacement
The central atom in the chlorite anion, is surrounded by:
two bonding and two unshared pairs of electrons
Consider the simple synthesis reaction combining solid potassium and liquid bromine. How many grams of solid Potassium bromide would be produced with 17.8 g of solid potassium?
54.2 g KBr
How many electrons are being shared by a triple bond? (What is total number of electrons represented by the triple bond?)
6
How many valence electrons are in a chlorine atom?
7
In the making of cheese (please note different pH levels result in different cheeses-more on pH in Chapter 9) , the bacteria ferment the sugar present in milk, called lactose (C12H22O11), into lactic acid (CH3CHOHCOOH), as follows: C12H22O11 + H2O ⇾ 4 CH3CHOHCOOH If we start with 332.9 g of lactose, how many liters (theoretically-we are assuming in this equation it is a gas for the purposes of this problem) of lactic acid can be produced?
87.1 L Lactic acid
Which of the following statements about Lewis structures is FALSE?
An octet is when an atom has 8 valence electrons. A covalent bond occurs when electrons are shared. All of the above statements are true.
Copper II chloride reacts with Sodium nitrate. If 15 g of Copper II chloride react with 20 g of Sodium nitrate, what is the limiting reactant? Use answer explanation and knowledge from 5.29 to answer.
CuCl2
Define limiting reactant.
Reactant that runs out first (smaller).
Balance the following equation by filling in the blanks (use a 1 if needed):
(1) FeCl3+ (3) NaOH ---> (1) Fe(OH)3 + (3) NaCl
Balance the following equation by filling in the blanks (use a 1 if needed):
(1) N2 + (3) H2 --> (2) NH3
Balance the following equation by filling in the blanks (use a 1 if needed):
(2) C8H18+ (25) O2 ---> (16) CO2+ (18) H2O
Balance the following equation by filling in the blanks (use a 1 if needed):
(2) NaBr+ (1) CaF2 ---> (2) NaF+ (1) CaBr2
Balance the following equation by filling in the blanks (use a 1 if needed):
(2) NaCl+ (1) F2 ---> (2) NaF+ (1) Cl2
Balance the following equation by filling in the blanks (use a 1 if needed):
(4) P+ (5) O2 ---> (2) P205
If we have the following equation: 1 cup flour + 2 eggs + 1/2 tsp baking powder---> 5 pancakes How many pancakes can we make with 3 cups of flour? Express your answer as a number only with three sig figs
15
How many valence electrons are in the nitrate ion?
24
Which of the following atoms is the largest?
Cs
What is the complete name of the most electronegative element in the periodic table?
Fluorine
What stoichiometry steps are specifically used to calculate amount of excess reactant left over?
Perform stoichiometry steps to convert from limiting reactant to excess reactant and then subtract that amount from the excess reactant given.
Classify the reaction: 4C5H9O (aq) + 27O2 (g) --> 20CO2 (g)+ 18H2O (l)
combustion
The central atom in the chlorate anion, is surrounded by:
three bonding and one unshared pair of electrons
What is the molecular geometry if you have 3 single bonds and 1 lone pair? Answer as a word only-may be more than one word.
trigonal pyramidal
Stoichiometry can be applied to the making of lots of foods we all enjoy such as
cheese chocolate wine beer
The following reaction: CH4+ 2O2-->CO2+ 2H2O is a reaction
combustion
What other applications might stoichiometry have?
cooking climate science-determining how much CO2 in air lab settings
What other reaction types can an acid-base reaction also be?
double replacement precipitation B and C
Neon has ____ valence electrons.
eight
What is a valence electron?
electrons in outermost shell
The reactant with amounts left over is called the ____ reactant
excess
What is unique about nitrogen gas?
forms a triple bond
2HCl(aq) + K2S(aq)--> H2S(g) + 2KCl (aq) What type of reaction is this? End your answer with the word reaction.
gas-evolving reaction
The _____ reactant is the reactant that gets used up first and determines the amount of product for a problem.
limiting
Which reactant gives us the theoretical yield?
limiting
Using Figure 6.7 on molecular geometries above, which structure would be shown for 4 lone pairs?
linear
What type of reaction does the following statement describe? electrons are transferred from one substance to another
redox
What type of bond does bromine gas have?
single bond
Which of the following is considered a single group of electrons?
single bond double bond triple bond all of these _
Classify the following reaction: Calcium and hydrochloric acid produce calcium chloride and hydrogen gas
single replacement
What is solubility of CaCl2?
soluble
STP stands for ______, _______ and ______ and is used to incorporate the conversion factor that 1 mole of an ideal gas occupies 22.4 L.
standard temperature pressure
Classify the reaction: 2NH3 (aq) +H2SO4 (aq) ---> (NH4)2SO4 (aq)
synthesis
What is the molecular geometry of CCl4?
tetrahedral
Copper II chloride reacts with Sodium nitrate. If 15 g of Copper II chloride react with 20 g of Sodium nitrate, how much excess reactant is left over in this reaction? Hint: Find out how much NaNO3 is used with limiting reactant
1.03 g 15CuCl2/ 134.45 g CuCl2 x 1 mol CuCl2/ 1 mol CuCl2 x 2 mol NaNO3/ 1 mol NaNO3 x 84.995 g NaNO3= 18.97 g NaNO3 needed to react with 15 g of CuCl2 Started with 20 g NaNO3 so 20 g NaNO3- 18.97 gNaNO3 used= 1.03 g NaNO3 left over
10.4 g of Arsenic reacts with 11.8 g of sulfur to produce 14.2 g of As2S3. Write the theoretical yield as a number only.
17.1
How many valence electrons are in sulfur dioxide?
18
Copper II chloride reacts with Sodium nitrate. If 15 g of Copper II chloride react with 20 g of Sodium nitrate, how many grams of Copper II nitrate are formed with four sig figs? Hint: Use limiting reactant starting amount.
20.93 g Cu (NO3) 2
What is the amount in liters that one mole of an ideal gas can occupy? Enter your answer as a number only.
22.4
Write the ionic equation for Iron III chloride and magnesium metal.
2Fe3+ (aq) + 6Cl- (aq) + 3Mg (s) -> 3Mg2+ (aq) + 6Cl- (aq) + 2Fe (s)
Zn + 2HCl → ZnCl2+ H2 How many moles of hydrogen are produced from the reaction of 3.0 moles of zinc with an excess of hydrochloric acid?
3.0 moles H2
Review the photosynthesis reaction: 6 CO2 (g) + 6 H2O (l) -> 6 O2 (g) + C6 H12O6(aq) How many grams of glucose can be synthesized from 58.5 g of CO2? Assume there is more than enough water present to react with all of the CO2. Express your answer as a number only with three sig figs.
39.9
Use the following photosynthesis reaction to perform the stoichiometry on this: 6CO2(g) + 6H2O(l) ⇒sunlight 6O2(g) + C6H12O6(aq) How many grams of glucose (C6H12O6) can be synthesized from 58.5 g CO2? Assume more than enough water to react with all of CO2.
39.9 g
For the following reaction, determine what the products of this reaction will be. When you have predicted the products, balance the equation and use a table of solubility products to determine which of the products (if any) will precipitate. Assume all reactions take place in water. ____ Cu(OH)2 + ___ H3PO4 --->
3Cu(OH)2 (aq) + 2H3PO4 (aq)---> 6H2O (l) + Cu3(PO4)2 (s)
Which of the following atoms have the following electron configuration 1s2 2s2 2p6 3s1?
Na
Write an equation for the precipitation reaction that occurs (if any) when solutions of sodium carbonate and copper (II) chloride are mixed.
Na2CO3(aq) +CuCl2(aq)⇒CuCO3(s) + 2NaCl (aq)
Why is the following reaction a redox reaction? Zn(s) + Fe2+ (aq)⇒ Zn2+ (aq) + Fe(s)
Zn transfers two electrons to Fe 2+.
Classify the reaction: 3HBr(aq) + Al(OH)3 (aq) ---> 3H2O (l) + AlBr3 (aq)
acid-base
If a molecule has 2 bonded pairs and 2 lone pairs, what will its shape be?
bent
The Lewis structure for oxygen gas includes which of the following?
double bond
Classify the reaction: 2NaBr (aq) + Ca(OH)2 (aq) ---> CaBr2(aq) + 2NaOH(aq)
double replacement
What specific business/marketing job utilizes the concept of excess reactants?
purchaser
Classify the following reaction: Magnesium and oxygen gas produce magnesium oxide
redox
Classify the following reaction: magnesium metal reacts with hydrochloric acid to form aqueous magnesium chloride and hydrogen gas
single replacement
How many core electrons are in a chlorine atom? Hint see larger group number.
10
1 cup flour + 2 eggs + 1/2 tsp baking powder ⇒5 pancakes How many pancakes can we make if we have 5 eggs? Assume we have enough of all other ingredients (more on this in section to follow).
12.5 pancakes but really only 12 then
Using the equation for the creation of ammonia gas. How many liters of ammonia gas would be produced if we start with 22.3 L of hydrogen? Write your answer as a number with correct sig figs only. Be sure to use the conversion factor of 22.4 L= 1 mole of any gas and you can use the shortcut if you would like.
14.9 L NH3 (g) 22.3LH2/ 22.4LH2x 1mol H2/ 3molH2x 2 mol NH3/ 1mol NH3 x 22.4 L NH3 or 22.3LH2/ 3L H2 x 2L NH3= 14.8666667 or 14.9 L NH3 with three sig figs.
How many moles of NaCl result from the complete reaction of 8.2 mol Cl2? Assume more than enough Na. 2Na(s) +Cl2(g) ⇒2NaCl(s) Answer with correct sig figs.
16 mol NaCl
Calculate limiting reactant and theoretical yield for the following reaction: 2As(s) +3S(l)⇒As2S3(s) when 10.4 g of As reacts with 11.8 g of S to produce 14.2 g As2S3.
17.1 LR is As.
Why is step 6 (above) not a subtraction only problem?
Because you cannot subtract one substance from a different substance (in algebra cannot subtract x from y).
For the following reaction, determine what the products of this reaction will be. When you have predicted the products, balance the equation and use a table of solubility products to determine which of the products (if any) will precipitate. Assume all reactions take place in water. Feel free to use outside solubility chart if needed. ____ Ca(OH)2 (aq) this is actually slightly soluble-more on this in future classes+ ____ HF (aq)--->
Ca(OH)2 (aq) + 2HF (aq) ---> 2H2O(l) + CaF2 (s) (CaF2 precipitates)
Lewis theory predicts that the formula for a compound between calcium and carbide is.
CaC2
What do resonance structures show?
Different structures for the same compound.
22.0 g of potassium reacts with 18.2 g of iodine. Calculate which reactant is limiting and how much product is made. LR=Limiting Reactant
I2 LR, 24.0 g KI
What is a spectator ion?
Ions that are unchanged on both sides of equation and do not participate in the reaction.
For covalent compounds, how does polyatomic ions typically impact these structures?
They add the amount of electrons needed.
How are the patterns seen in the periodic table for ionization energy and electron affinity related?
They both have the same trends seen.
Refer to the following chemical equation to answer this question: H2 + O2 ---> 2H2O Explain this in words.
Two hydrogen atom combine with one oxygen molecule to produce two water molecules.
